Play around with the Computer Language Benchmarks Game. It's good at showing what some of the trade-offs are. Of course, it's really not very scientific, but it gives you an idea. http://shootout.alioth.debian.org/

You'll usually see C, C++, Java, Haskell, OCaml, Fortran, Scala, and Lisp in the 1-10x range (of the fastest solution). They all should be reasonably competative on most things, and so you might make your decision based on personal preference and available libraries.

This is in contrast to things like Ruby, Perl, and Python which are often take 100x the time.

> http://shootout.alioth.debian.org/gp4/

Please choose the up-to-date measurements instead of these.

I have used two varieties of Lisp: Common Lisp and Clojure. Both have dynamic typing with optional "type hints", which allow you to get the performance of a statically typed language. Type hints are typically used only in small doses, for parts of your code that are very performance critical.

>(No Fortran please, I suppose).

I've got a friend who works on simulating air currents around areroplanes real-time. They have to do everything in Fortran but he says that Fortran-99 is actually pretty pleasant. Pretty pleasant compared to older fortrans perhaps :)

Haskell does well in benchmarks but this hides the fact that its performance is very unpredictable. Try it and you'll see what I mean. Also, Common Lisp does well in benchmarks but only after a lot of declarations are added which make the code nearly unreadable.

Personally I get the best results from the MLton SML compiler. OCaml is also pretty fast and more practical. YMMV.